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Miley Cyrus is making her debut as the new face of Marc Jacobs. 

On Wednesday, the singer tweeted the first ad from the designer's spring collection, showing off a more mature, covered-up look.  The pop star is shown sitting with her arms crossed and a moody expression, wearing a long-sleeved navy top and red shorts.  Her tongue remains firmly planted inside her mouth and her signature blonde 'do is styled with a sophisticated touch. 

Miley has been a muse of the American designer's since last year.  In October, she was the one to present him with a special honor at the Fashion Group International's Night of the Stars.  His green-sequined gown design helped the singer earn a spot on "Time's" 2013 Best Dressed list. 

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